From: Peter Zijlstra <peterz@infradead.org>
To: Zachary Amsden <zamsden@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
axboe@kernel.dk, hch@infradead.org, akpm@linux-foundation.org,
Paul.Clements@steeleye.com, tytso@mit.edu,
Tejun Heo <tj@kernel.org>, miklos <miklos@szeredi.hu>
Subject: Re: [PATCH] Allow userspace block device implementation
Date: Mon, 27 Jul 2009 22:24:44 +0200 [thread overview]
Message-ID: <1248726284.6987.2068.camel@twins> (raw)
In-Reply-To: <4A6E0431.30000@redhat.com>
On Mon, 2009-07-27 at 09:46 -1000, Zachary Amsden wrote:
> Can you swap over NBD? Assuming one had pinned the userspace program
> and it pre-allocated all memory so no pagein / alloc was required, would
> it be deadlock proof? I believe there are structure allocations
> required for the socket implementation that go beyond the basic BIO
> allocations, therefore making it impossible. In /theory/, one should be
> able to swap over this device. In practice, it's probably a really bad
> idea.
I've got patches to make swap over network work, with those swap over
NBD works until you loose connection. NBDs great weakness (aside from
funny code) is that it does the connection management in userspace,
which makes recovering from connection loss when swapping over it
utterly impossible.
next prev parent reply other threads:[~2009-07-27 20:23 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-27 9:57 [PATCH] Allow userspace block device implementation Zachary Amsden
2009-07-27 12:56 ` Peter Zijlstra
2009-07-27 13:25 ` Alan Cox
2009-07-27 19:46 ` Zachary Amsden
2009-07-27 20:24 ` Peter Zijlstra [this message]
2009-07-27 21:02 ` Alan Cox
2009-07-28 1:21 ` Tejun Heo
2009-07-28 3:53 ` Zachary Amsden
2009-07-28 10:27 ` Alan Cox
2009-07-28 16:00 ` Linus Torvalds
2009-07-28 18:36 ` Kyle Moffett
2009-07-28 18:51 ` Linus Torvalds
2009-07-28 19:07 ` Alan Cox
2009-07-28 19:49 ` Andi Kleen
2009-07-28 20:50 ` Linus Torvalds
2009-07-28 21:09 ` Andi Kleen
2009-07-28 22:56 ` Theodore Tso
2009-08-07 18:08 ` Pavel Machek
2009-08-10 22:47 ` Zachary Amsden
-- strict thread matches above, loose matches on Subject: below --
2009-07-28 20:37 devzero
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